Environmentally safe, broad spectrum insecticide

ABSTRACT

A combination of pyrethrum and fatty acid salt materials has been formulated which produces a stable, commercially useful, and environmentally safe pesticide. The specific composition comprises an aqueous solutioon having a pH within the range of 7.5 to 8.8; an aqueous solution comprising about 50% by weight of monocarboxylic acids and their alkali metal salts, where the acid mixture is at least 70% oleic acid and 6% linoleic acid; a pyrethrum extract; a solvent for the pyrethrum, which is preferably a 2-6 carbon alcohol; a trace amount of an antioxidant. The composition is effective against insects of at least the orders Homoptera, Coleoptera, Dermaptera, Hemiptera, and Lepidoptera, and against crustacea of the order Isopoda.

BACKGROUND OF THE INVENTION

This invention relates to an environmentally safe insecticidecomposition. More particularly, the invention features a specificinsecticide formulation consisting of certain fatty acid soaps andpyrethrins together with a stabilizer and carrier, which formulationexhibits improved insecticidal properties as compared with theindividual components, is effective in the control of a broad range ofleaf eating and other insects, is environmentally safe, and hasacceptably low phytotoxicity.

The use of insecticides has greatly enhanced agricultural productivity,but it has become apparent that there are limits to the amount ofpetrochemical-based materials that safely can be absorbed into theenvironment. Catastrophic, unanticipated, relatively long term effectsexperienced with materials such as DDT have increased awareness of thepotentially dangerous environmental impact of widespread use ofsythetics, contributed to the creation of regulatory agencies chargedwith protecting the environment, and promoted the development of potent,but apparently less dangerous insecticidal materials made frompetrochemicals. These new insecticides are nevertheless far from idealfrom the point of view of environmental safety, and sometimes collect infood and fresh water resources.

Recently, natural insecticidal materials such as bacterial preparationslethal to insects have been available commercially. However, thepotential of non-bacterial, natural materials having insecticidalproperties has largely been ignored, presumably because of the highercost and lower insecticidal activity of such known natural substances.

Salts of fatty acids, primarily sodium or potassium fatty acid soaps,recently have been used commercially as an insecticide. Compositionshaving excellent insecticidal properties which exploit these salts areavailable commercially under the trademark SAFER INSECTICIDAL SOAP. Thisproduct accordingly constitutes an exception to the trend noted above.These fatty acid soaps are naturally occurring materials having no knownlong term environmental effects. They are very effective against mitesand soft bodied insects such as aphids and whiteflies, but lesseffective against other types of insects.

Pyrethrum was used commercially many years ago as an insecticide,primarily in the form of "oleoresin of pyrethrum". Oleoresin ofpyrethrum is an archaic pharmaceutical term for an ether extract of thecinerariaefolium variety of chrysanthemum. It contains volatile oils andcomponents having insecticidal properties, called pyrethrins, jasmolins,and cinerins. These materials are known to be toxic to insects,essentially non-toxic to mammals, to lack persistence in theenvironment, and to be characterized by negligible biologicalmagnification in the food chain.

One major problem with the use of these materials (hereinafter"pyrethrins") as insecticides is their high cost per unit dose. Attemptsto extend the efficacy of the pyrethrins to provide economic feasibilityhave not been commercially successful. An example of such a compositioncomprising a mixture of saponified organic acids, i.e., salts of coconutoil, and pyrethrins was sold commercially under the trademark Red Arrowabout 55 years ago. However, these mixtures did not solve the expenseproblem because of their high pyrethrin content, about 40% by weight,and because the coconut oil soaps contributed little to theirinsecticidal efficacy. In fact, most commercially available fatty acidsoap compositions contain an excess of alkali which is thought topromotes hydrolysis and inactivation of pyrethrins. Pyrethrin-basedinsecticides also degrade rapidly in storage and in use.

Other materials which have been used to extend the efficacy ofpyrethrins are toxic not only to insects but also to a variety of plantsand animals. One material often suggested for use with pyrethrins ispiperonyl butoxide. While this type of composition can produce a verypotent insecticide, high doses can cause nausea in many animalsincluding man, and the compositions are significantly phytotoxic. Othercombinations of insecticides and pyrethrins have either presentedsimilar toxicity concerns or loss of effectiveness due to inactivationof the pyrethrins.

It is an object of this invention to provide an insecticide formulationcomprising natural, biodegradeable materials which are inexpensive,non-toxic to a wide variety of plants and animals, and effective againsta broad spectrum of insect life. Another object is to provide aspecific, environmentally safe insecticidal combination of naturalproducts which has a commercially acceptable shelf life, low, acceptablephytotoxicity, and low cost.

These and other objects and features of the invention will be apparentfrom the description and the claims which follow.

SUMMARY OF THE INVENTION

The present invention features a specific insecticidal solutioncomprising a combination of active, readily biodegradable insecticidalmaterials in specific weight ratios formulated to retain, and indeed, toenhance the insecticidal effectiveness of the individual insecticidalmaterials. The insecticide is economical to use, toxic to many differenttypes of insect pests, and substantially non-toxic to other animals andplants.

The insecticidal formulation of the invention is based on the discoverythat contrary to the general teachings of the prior art, a combinationof pyrethrins and fatty acid salt materials can be formulated to producea stable, commercially very useful, and environmentally safe insecticidethat is effective to protect plants against a wide variety of insect andrelated pests.

Accordingly, the invention provides a readily biodegradeable,environmentally safe, storage stabilized, aqueous, insecticidal solutionfor application to decorative and crop plants. The solution is effectiveto control plant damage caused by many chewing and sucking insects. Itconsists essentially of an aqueous solution having a pH within the rangeof 7.5 and 8.8, preferably 8.0-8.5, and containing the followingingredients in the following relative parts by weight:

A. Between 30 and 50 parts of an aqueous solution comprising about 50percent by weight of a mixture of monocarboxylic acids and their alkalimetal, preferably potassium, salts. The monocarboxylic acid mixturecomprises at least 70 percent oleic acid and its alkali metal salt andat least 6 percent linoleic acid and its alkali metal salt. Theremaining components of the carboxylic acid mixture, if any, comprisesother monocarboxylic acids (or their salts) having less than 21 carbonatoms or other inert materials.

B. Between 1.0 and 2.0 parts of a pyrethrum extract comprising about 20percent of a mixture of insecticidally active substances selected fromthe group consisting of pyrethrin I, pyrethrin II, cinerin I, cinerinII, jasmolin I, and jasmolin II;

C. Between 3 and 20 parts of a solvent for the insecticidally activepyrethrum extract substances comprising a low molecular weight alcohol.Preferably, the alcohol has 2-6 carbon atoms. Excellent results havebeen obtained with isopropyl alcohol.

D. A trace amount of an antioxidant, preferably a hydroxylated aromaticmaterial, and most preferably butylated hydroxytoluene.

The composition is effective on application to a plant at a dilution inwater such that the applied solution contains at least about 0.5 percentby weight of the monocarboxylic acid mixture and at least about 0.005percent of the mixture of insecticidally active pyrethrum extractsubstances. Upon application, the composition rapidly kills insectspecies from at least the orders Homoptera, Coleoptera, Dermaptera,Hemiptera, and Lepidoptera, and from crustacea species from the orderIsopoda. More specifically, application of the solutions is effectiveagainst species from the families Homoptera:Aphididae,Homoptera:Aleyrodidae, Homoptera:Coccidae, Homoptera:Psyllidae,Coleoptera:Chrysomelidae, Coleoptera:Tenebrionidae,Lepidoptera:Arctiidae, Lepidoptera:Lasiocampidae,Lepidoptera:Tortricidae, Lepidoptera:Pieridae, andLepidoptera:Noctuidae. These orders and families include essentially allnorthern hemisphere insects which damage ornamental plants, trees, andfood and other crops.

The insecticidal solutions also are effective in the control ofmosquitoes, fleas, lice, and ticks, and accordingly may be used, forexample, to protect pets and their resting places in the home.

The solution of the invention preferably is marketed as a concentratewherein ingredient A is present at about 40 percent by weight andingredient B is present at about 1.5 percent by weight. Preferably,ingredients A through D together comprise at least about 40 percent byweight of the concentrate. Dilution of the concentrate with water (20:1)produces a ready-to-use solution having the insecticidal propertiesnoted above and comprising about 2.0 percent ingredient A (1.0% fattyacid salts) and 0.075 percent ingredient B (0.015% active pyrethrumextract components).

The insecticide of the invention is useful in protecting apples,avocados, grapefruits, lemons, oranges, tangerines, peaches, nectarines,apricots, pears, almonds, pecans, walnuts, kiwi fruit, blackberries,logan berries, raspberries, strawberries, and grapes, against insectsincluding Japanese beetles, flea beetles, weevil adults, caterpillars,aphids, leaf hoppers, psyllids, scale crawlers, and sawfly larvae. Inaddition to commercial or vegetable garden protection, the insecticideof the invention can be used to protect lawns, turf grass, ornamentaltrees and shrubs, flowers, and house plants against a variety ofinsects. For example, the insecticide protects lawns against chinchbugs, lawn moth, sod webworm and army ants, and ornamental trees andshrubs against aphids, beetles, caterpillars, lace bugs, box elder bug,treehoppers, psyllids, sawflies, scales, and woolly aphids. Essentiallycomplete insect protection is provided for ornamental trees and shrubsincluding azaleas, camellias, cacti, dogwood, rhododendrons, evergreens,and broad-leafed shade trees. The insecticide of the invention has beenshown to provide effective protection for flowers including asters,carnations, chrysanthemums, geraniums, marigolds, petunias, and rosesagainst attack by aphids, flea beetles, Japanese beetles, caterpillars,and whitefly.

DETAILED DESCRIPTION

The insecticide of the invention employs two insecticidally activematerials: a pyrethrum extract; and a fatty acid soap of specificcomposition. The weight ratio of these two active components and the PHof the composition are important to the success of the invention.Significant deviations from the ratio result in rapid degradation of theimportant properties of the formulation. Specifically, the insecticidalefficacy and/or shelf and field stability are adversely affectedprogressively. Of the two active components, the pyrethrum is by far themore insecticidally potent on a weight basis. Thus, decreasing thepyrethrum extract content reduces the insecticidal efficacy and pestspectrum response until, at zero pyrethrum, the response ischaracteristic of the fatty acid component alone. Increasing thepyrethrum content, on the other hand, does not necessarily increaseefficacy, as increasingly over time, the soap component tends to reactwith and reduce the efficacy of the pyrethrum extract. Lowering thesolutions pH below about 7.5 progressively increases the phytotoxicityof the composition. Increasing the pH leads to pyrethrin degradation.The combination of components yields unexpected and synergistic insectkills on some species, i.e., a more effective kill rate as compared withthe kill rate of the components individually.

The insecticide of the invention can be stored as a concentrate and thendiluted for use, or may be kept in a ready-to-use form. A preferredconcentrated form comprises about 40% fatty acid soap solution (50%fatty acids, a major amount of which is in alkali metal, preferablypotassium, salt form), and 1.0% to about 1.5% by weight of a purifiedpyrethrum extract (20% by weight pyrethrins and other active extractsubstances). Upon dilution about 20:1 with water, a ready-to-usesolution results comprising about 1.0% fatty acid component and betweenabout 0.01% and 0.015% active pyrethrum compounds.

The composition is manufactured by mixing together a solution of saltsof fatty acids, water, an alcohol which acts as a carrier and solventfor the pyrethrum, an antioxidant, and the pyrethrum extract, and thenacidifying the mixture as needed, e.g., with HCl, to set the pH.

The salts of fatty acids preferably consists of an aqueous solutioncomprising about 49% by weight of a mixture of potassium salts of fattyacids and unneutralized fatty acids. A suitable solution is availablecommercially from Safer, Inc. of Wellesley, Mass. under the trademarkSafer Insecticidal Soap. The composition of this product varies slightlyfrom batch to batch, but always includes at least about 70% salt (oracid form) oleic acid, and at least about 6% salt (or acid form)linoleic acid. The remainder of the solutes comprise other fatty acidsor salts having between 12 and 20 carbon atoms. The soap component ispresent in the concentrate at levels in the range of 15 to 25,preferably about 20, percent by weight.

The purified pyrethrum ether extract comprises about 20% by weight of amixture of pyrethrin I and II, cinerin I and II, and jasmolin I and II.It is present in the concentrate at levels in the range of 1.0 to 2.0,preferably about 1.5, percent by weight. A suitable purified pyrethrumextract is commercially available from Fairfield American Corporation,Newark, N.J.

Other components of the concentrate include alcohol, preferablyisopropyl alcohol, which comprises between about 3 and 20 percent,preferably about 10 percent, by weight of the aqueous insecticideconcentrate, and an effective amount, e.g., a trace amount, of anantioxidant, preferably a butylated hydroxytoluene, which constitutesapproximately 0.02% by weight. The isopropyl alcohol can be purchased,for example, from Valley Products of Memphis, Tenn. The butylatedhydroxytoluene is available from, for example, Melville SyntheticOrganics, Inc., of Pittsburgh, Pa. The remainder of the insecticideconcentrate constitutes diluents, primarily water, and inerts introducedwith the fatty acid and pyrethrum components.

The currently preferred embodiment of the concentrate of the inventionis made by mixing and gently agitating 400 parts Safer InsecticidalSoap, 485 parts water, 100 parts isopropyl alcohol, 0.2 parts butylatedhydroxytoluene, and 15 parts purified pyrethrum extract (20%). Asformulated, the concentrate has a PH within the range of 7.5 to 8.8,preferably 8.0. This is diluted 20:1 with water before application.

This product exhibits a combination of vertebrote and phytotoxicity, andready insecticidal activity, spectrum response, low biodegradeabilityunavailable in any composition known to applicants. Furthermore, unlikesimilar composition produced heretofor, both the concentrate and theready-to-use solution have commercially acceptable storage stability.

The following examples illustrate the lace of toxicity, efficacy, andstorage stability of the insecticidal composition of the invention.

EXAMPLE 1

A highly concentrated form of an insecticide comprising fatty acid saltsand pyrethrum extract was tested for animal toxicity. Rats were used fortesting oral and inhalation toxicity, rabbits for dermal toxicity,rabbits in a Draize test for primary eye irritation and in a test forprimary skin irritation, and guinea pigs for dermal sensitivity studies.The solution used comprised 40% Safer Insecticidal Soap and 0.4%pyrethrin (unless otherwise indicated below), a concentrationapproximately double that of the preferred concentrate and about 40times that of the ready-to-use solution. The following results indicatethat the insecticide of the present invention, even in highlyconcentrated form, is substantially non-toxic to animals.

A. Oral LD₅₀ in Rats

Rats were fed various amounts of the concentrated insecticide, rangingup to 10.0 g/kg of body weight, in order to determine the oral LD₅₀, thedosage at which 50% of the rats died. No mortality of the rats occurredat this dose level and the testing was suspended.

B. Acute Dermal LD₅₀ in Rabbits

Rabbits were exposed to various amounts of the concentrated insecticidewith the highest dosage being 2.0 g/kg of body weight, in order todetermine a dermal LD₅₀. No mortality occurred among the rabbits at thisdose level and essentially no symptoms of systemic toxicity weredetected after day six or in postmortem examinations after a 2.0 g/kgbody weight dermal application.

Acute Inhalation LD₅₀ in Rats

Rats were exposed to atmospheric concentrations up to 12.75 ml/l of theconcentrated insecticide, of which 5.64 ml/l was respirable, todetermine an inhalation LD₅₀. There was no mortality among the ten ratsexposed over the entire fourteen day observation period.

D. Draize Test

The Draize test, see "Eye Irritation Testing", EPA-560 (11-82-001),published by the United States Environmental Protection Agency Office ofPesticides and Toxic Substances, was used to measure primary eyeinflammation by contact with a concentrate comprising 20% InsecticidalSoap and 0.4% pyrethrin. This highly concentrated version of theinsecticide was classified as a class three irritant after testing. Whenthe eyes of the test animals were rinsed out twenty to thirty secondsafter contact with the solution, there was essentially no irritation.

E. Primary Skin Irritation Test

Primary skin irritation studies using a 0.4% pyrethrum extract, 20%Insecticidal Soap mixture resulted in a finding of moderate to severeirritation, but essentially no irritation was observed at seven and ninedays. In fact, the skin had returned to normal by day eight in all thetest animals.

F. Dermal Sensitivity Studies

In dermal sensitivity studies using guinea pigs, the highly concentratedform of the insecticide was found to be very mildly sensitizing.

This Example illustrates that the insecticide of the invention, even ina highly concentrated form, has exceptionally low toxicity.

EXAMPLE 2

In this Example, a comparison of kill effectiveness was made betweenInsecticidal Soap without pyrethrum, the pyrethrum extract itself, andan insecticide comprising a combination of the two formulated inaccordance with the ratio disclosed herein. The test involved applyingthe same amount of the sample to variegated cutworm and measuringmortality percentages. Table 1 shows the results of this experiment. Asis obvious from the Table, the insecticide of the present invention doesnot show purely additive insecticidal properties with respect to thisparticular insect pest, but rather an unexpected, synergistic killratio.

                  TABLE 1                                                         ______________________________________                                                    % Mortality                                                                   (Weight Ratio 50:1)                                                             Neutral  Pyre-                                                  Mixture       Soap     thrum   Expected                                                                             Observed                                ______________________________________                                        0.1%  Neutral Soap*                                                                             2.8%     31.4% 34.2%  65.7%                                 0.002%                                                                              Pyrethrins                                                              0.05% Neutral Soap*                                                                             8.6%     20.0% 28.6%  45.7%                                 0.001%                                                                              Pyrethrins                                                              ______________________________________                                         *potassium oleate, neutralized with HCl, the most active component of         Insecticidal Soap.                                                       

EXAMPLE 3

As previously noted, the insecticide of the invention has broadinsecticidal activity. In order to demonstrate this activity, theinsecticide was tested on a number of different species of insects. Theresults were compared with a positive control, MGK-7352, which contained0.02% pyrethrins and piperonyl butoxide, and a negative control,distilled water. Table 2 lists a number of different insects and amortality percentage obtained using the insecticide of the invention.SAP101 is a preferred form of the insecticidal solution of theinvention, comprising 2% potassium Insecticidal Soap and 0.05% pyrethrumextract. Values in parentheses are duplicate runs of the same test.

                  TABLE 2                                                         ______________________________________                                                  PERCENT MORTALITY                                                                                     DISTILLED                                   INSECT      SAP101     MK7352     WATER                                       ______________________________________                                        Cabbage Aphids                                                                            98.9   (98.9)  100.0                                                                              (97.7)                                                                              14.4 (3.4)                              Bean Aphid  98.0           98.0       12.0                                    Yellow Mealworm                                                                           75.0           93.75      0.0                                     Adult                                                                         Yellow Mealworm                                                                           100.0          50.0       6.25                                    Larvae                                                                        Milkweed Bug                                                                              80.0           72.5       0.0                                     Larvae                                                                        Milkweed Bug                                                                              100.0          100.0      6.7                                     Adult                                                                         Eastern Spruce                                                                            100.0  (95.0)  100.0                                                                              (100.0)                                                                             0.0  (2.5)                              Budworm                                                                       Imported Cabbage-                                                                         100.0  (97.5)  100.0                                                                              (100.0)                                                                             0.0  (0.0)                              worm                                                                          Cabbage Looper                                                                            100.0          100.0      2.0                                     Larvae                                                                        ______________________________________                                    

As is exemplified by the results set forth in Table 2, the 2% IS/0.05%pyrethrum solution of the invention is effective in controlling a widevariety of insects. Other tests using different concentrations of soapand pyrethrins, still within the scope of the claims, have yieldedsimilar results for a wide variety of insects.

EXAMPLE 4

To assess product stability, the pyrethrin content of both theconcentrate and the ready-to-use solution was measured after the testbatches were freshly prepared, and again after normal and acceleratedaging. Analyses were conducted in duplicate together with internalstandards (di-n-butylphthalate) using gas/liquid chromatography.

On day one, a solution of ready-to-use product was prepared and placedin storage at room temperature in a brown glass bottle. The contentswere sampled and analyzed four months later. The analyses resulted in afinding that 85.8% of the active pyrethrum content remained.

In another experiment, a sample of the concentrate was stored in an ovenat 50 degrees C. for 34 days. Upon analysis, it was determined that86.1% of the pyrethrum actives remained. When the experiment wasrepeated with a concentrate sample containing twice the normal (5.0%)isopropyl alcohol content, 74.2% of the pyrethrum actives remained.

Two samples of ready-to-use solution were prepared, one containing atrace quantity of butylated hydroxytoluene (50 ppm), and one free ofantioxidant. After accelerated aging in an oven at 50 degrees C. for 33days, the former preparation was determined to contain 81.4% of theoriginal pyrethrum active content. The sample containing no antioxidantwas determined to contain no active pyrethrums.

EXAMPLE 5

Experiments were conducted to evaluate the foliar and floralphytotoxicity of the insecticidal solution, as fatty acid salts havebeen observed to exhibit herbicidal activity. A representitive number ofvegetables, ornamental trees and shrubs, and floral plants were testedin a greenhouse. The plants were sprayed to run-off, and damage wasassessed after 24 hours (for floral damage) and after 2-7 days (forfoliar damage). The test samples were varied in pH, alcohol content,active fatty acid soap content, and pyrethrum content. As controls, asolution of 0.02% pyrethrins with piperonyl butoxide, and distilledwater were used.

Foliar damage assessments were made using a 0-10 scale (0=healthy,10=complete necrosis and death). A scale rating of 1 indicates that somedamage occurred but was noticeable only on close inspection. A rating of2 indicates damage which would be noticed on more casual inspection, butwould involve less than 10% of the sprayed surface, and would beunlikely to involve permanent damage. A rating of 5 indicates 50% of thefoliar surface is necrotic. Floral damage assessments were made using a0-3 scale (0=healthy, 3=complete necrosis). Within this scale a 1indicates some damage observed on close inspection, while a rating of 2indicates unacceptable damage.

The results indicate that the ready-to-use product as formulated wascharacterized by only low, acceptable phytotoxicity toward all plantspecies tested, levels far below the piperonyl butoxide testpreparations. Of the vegetables tested, only spinach showed a meandamage rating over 2. Preparations of lower pH generally were morephytotoxic. Of the ornamentals tested, only schizanthus showedunacceptable ratings of 2.67±0.82. A ready-to-use formulation having apH of 7.1 produced a damage rating of 4 on three sensitive speciestested. No unacceptable rating were noted on trees or shrubs.

In the floral tests, among the plants tested, unacceptable damageoccurred with a ready-to-use formulation only on rhododendron blooms.Severe damage also was observed with solutions formulated at pH 7.15 onsome species. The ready-to-use product of the invention described abovegave an acceptable rating of 1.3±0.58.

In general, it was found that the solutions of the invention were farless phytotoxic than the butoxide-containing preparations. It alsoshould be noted that phytotoxicity testing in the greenhouse isgenerally much more rigorous than the testing of field grown plants,which are generally healthier and hardier.

The foregoing Examples are purely illustrative and are not meant tolimit the scope of the following claims.

What is claimed is:
 1. A readily biodegradeable, environmentally safe,storage stabilized, aqueous, insecticidal solution for application todecorative and crop plants, said solution being effective to controlplant damage from a wide range of chewing and sucking insects, saidcomposition consisting essentially of:an aqueous solution having a pHbetween about 7.5 and 8.8 and containing the following ingredients inthe following relative parts by weight:A. between 30 and 50 parts of anaqueous solution comprising about 50 percent by weight of a mixture ofmonocarboxylic acids and the alkali metal salts thereof,saidmonocarboxylic acid mixture comprising at least 70 percent oleic acidand its alkali metal salts and at least 6 percent linoleic acid and itsalkali metal salt; B. between 1.0 and 2.0 parts of a pyrethrum extractcomprising about 20 percent by weight of a mixture of isecticidallyactive substances selected from the group consisting of pyrethrin I,pyrethrin II, cinerin I, cinerin II, jasmolin I and jasmolin II; C.between 3 and 20 parts of a solvent for said insecticidally activepyrethrum extract substances comprising a low molecular weight alcohol;and D. a trace amount of an antioxidant, said composition beingeffective on application to a plant at a dilution in water such that theapplied solution contains at least about 0.5% by weight of saidmonocarboxylic acid mixture and at least 0.005% by weight of saidmixture of said insecticidally active pyrethrum extract substances toprovide protection against plant damage from infestation by insectspecies from the orders Homoptera, Coleoptera, Dermaptera, Hemiptera,and Lepidoptera, and from crustacea species from the order Isopoda. 2.The solution of claim 1 wherein, on application, said solution iseffective against species from the families Homoptera:Aphididae,Homoptera:Aleyrodidae, Homoptera:Coccidae, Homoptera:Psyllidae,Coleoptera:Chrysomelidae, Coleoptera:Tenebrionidae,Lepidoptera:Arctiidae, Lepidoptera:Lasiocampidae,Lepidoptera:Tortricidae, Lepidoptera:Pieridae, andLepidoptera:Noctuidae.
 3. The solution of claim 1 wherein the alkalimetal salt is a potassium salt.
 4. The solution of claim 1 wherein therelative ratio of ingredients A:B is about 40:1.5.
 5. A concentrate ofthe solution of claim 1 for dilution with water to produce aninsecticide suitable for spray application wherein ingredients A throughD together comprise at least about 40 percent by weight of saidsolution.
 6. The solution of claim 1 wherein said antioxidant is ahydroxylated aromatic compound.
 7. The solution of claim 6 wherein saidhydroxylated aromatic compound is butylated hydroxytoluene.
 8. Thesolution of claim 1 wherein said alcohol has between 2 and 6 carbonatoms.
 9. The solution of claim 8 wherein said alcohol is isopropylalcohol.
 10. The solution of claim 1 having a pH within the range of 8.0to 8.5.